Evidence for the Existence of Cancer Stem Cells

A pool of stem cells has been found to fuel the growth of intestinal tumors in mice, a Dutch team reports. The researchers say this finding provides support for the controversial cancer stem cell hypothesis. If such stem cells existed, they could be an important target for new cancer drugs.

By studying mice expressing multicolor reporter genes, Arnout Schepers and colleagues from the University Medical Center Utrecht in Utrecht, The Netherlands, detected and monitored the fate of a candidate stem cell for intestinal adenomas, a precursor to intestinal cancer.

By “lineage retracing” using the multicolor Cre-reporter R26R-Confetti, the researchers demonstrate that the crypt stem cell marker Lgr5 also marks a subpopulation of adenoma cells that fuel the growth of established intestinal adenomas. These cells, which represent about 5–10% of the cells in the adenomas, generate additional Lgr5+ cells as well as all the other adenoma cell types.

The authors note that although adenomas represent only the first stage of intestinal tumorigenesis, the composition of the tumors suggests that cancer stem cells do indeed exist.

The paper is titled “Lineage Tracing Reveals Lgr5+ Stem Cell Activity in Mouse Intestinal Adenomas”, and is published online by the journal Science.